RE: nRF52840-DK SPI communication with digital potentiometer

parraghb — Sat, 18 Jan 2020 11:17:34 GMT

If I clear this __WFE line, the code still doesn't work. I think the problem will be in the slave. Please check MCP datasheet page 18. Data line and transfer are good, I don't know where is the problem.

I used while(1){}; line, because I want use just once SPI transfer. Later here will be sleep mode.

"You are starting multiple SPI transfers without waiting for the previous to complete? is that what you intended?"

No, just I want use two slave. Sinus generator (slave 1), who get 90-104 line's data, and digital potentiometer (slave 2), who get 106,107 line's data. Singen data lines are ok, work well, but digpot no. I just looked at them separately.

RE: nRF52840-DK SPI communication with digital potentiometer

Susheel Nuguru — Fri, 17 Jan 2020 09:14:41 GMT

Haven't used MCP4110 myself so I cannot answer anything specific to that sensor.

        while (!spi_xfer_done)
        {
           __WFE();
        }

Waiting for a flag and using only __WFE could cause problems. To understand, read this thread. I see that the SPI example in the SDK is written this way, but I think it could be changed.

        while(1){};

so you want your app to be low power for certain time and then busy loops indefinitely (not low power anymore). I am sure this is not what you want to do!!!??

You are starting multiple SPI transfers without waiting for the previous to complete? is that what you intended?